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Synfacts 2022; 18(11): 1221
DOI: 10.1055/s-0042-1753012
Metals in Synthesis

The Hirao Reaction: Palladium-Catalyzed Cross-Coupling of Dialkyl Phosphites with Aryl Halides

Contributor(s):
Martin Oestreich
,
Hendrik F. T. Klare
,
Phillip Pommerening
Hirao T, *, Masunaga T, Ohshiro Y, Agawa T. Osaka University, Japan
A Novel Synthesis of Dialkyl Arenephosphonates.

Synthesis 1981; 56-57
DOI: 10.1055/s-1981-29335
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Key words

C(sp2)–P bond formation - palladium catalysis - phosphonates

Significance

In 1981, Hirao and co-workers disclosed the direct cross-coupling of aryl halides with dialkyl phosphites in the presence of a palladium(0) catalyst and an amine base to give the corresponding aryl phosphonates. In contrast to the Michaelis–Arbuzov reaction, this protocol enables the facile formation of C(sp2)–P bonds.


 

Comment

While most products were isolated in good to excellent yields, the cross-couplings of para-hydroxyphenyl and para-aminophenyl halides were ineffective. The substrate scope was successfully extended to vinyl halides (Tetrahedron Lett. 1980, 21, 3595), affording the corresponding vinyl phosphonates in high yields (see grey box).


 

 

Publication History

Article published online:
18 October 2022

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